Update Changelog

Author: Daraan

CHANGELOG.md

@@ -29,6 +29,8 @@ aliases that have a `Concatenate` special form as their argument.
 - Fix that lists and ... could not be used for parameter expressions for `TypeAliasType`
   instances before Python 3.11.
   Patch by [Daraan](https://github.com/Daraan).
+- Fix error on Python 3.10 when using `typing.Concatenate` and 
+  `typing_extensions.Concatenate` together. Patch by [Daraan](https://github.com/Daraan).
 
 # Release 4.12.2 (June 7, 2024)